In general, rotary power tools are light-weight, handheld power tools capable of being equipped with a variety of accessory tools and attachments, such as cutting blades, sanding discs, grinding tools, and many others. These types of tools typically include a generally cylindrically-shaped main body that serves as an enclosure for an electric motor as well as a hand grip for the tool. The electric motor drives an output shaft to rotate at high speeds. The output shaft is equipped with an accessory attachment system that enables accessory tools to be releasably secured to the power tool. In some rotary tools, a cutting wheel or disk is used as the accessory tool to cut or machine a workpiece, which may include a rod, a screw, a sheet of material, a pipe, and the like.
One issue with conventional rotary tools is the potential for the rotary tool to bind, or catch, in the workpiece. When the tool binds, the blade stops while the motor continues operating. The continued operation of the motor causes the tool to quickly rotate in the opposite direction of the tool rotation, potentially jerking away from the workpiece being cut. This can lead to a dangerous situation in which the user loses control of the tool, potentially contacting undesired objects with the cutting disk. It would be desirable therefore to provide a mechanism to limit rotation of the rotary tool when the tool binds in the workpiece.
Another common use of rotary tools using a cutting disk is to form a slot in a screw head. However, it is difficult to accurately form a slot centered in a screw head since the tool has a tendency to slide along the surface of the screw head before the cut begins. Thus, it would be desirable to provide a mechanism that facilitates accurate alignment of the rotary tool for slotting a screw head.
Additionally, when using a rotary tool with a cutting disk, the material removed from the workpiece is ejected from the cutting disk, potentially causing sparks and debris to land on a user or in other undesirable locations. It would therefore be desirable to provide a mechanism to reduce the amount of debris ejected from the immediate area of the cutting disk.